The present invention relates to an optical control apparatus which energizes a semiconductor laser for emission of a laser beam from the semiconductor laser, and more particularly to an optical control apparatus which controls energizing current for the semiconductor laser to adjust the light power of the laser beam to a target light power.
A known image forming apparatus which forms an image by an electrophotographic method such as a laser printer includes a semiconductor laser as a light source used for exposing a photosensitive body. This type of image forming apparatus requires adjustment of the light power of a laser beam to a predetermined power so as to obtain a desired concentration of a formed image.
According to a proposed technique, the light power of a laser beam is kept constant under the control over energizing current for a semiconductor laser by monitoring the light power of the laser beam from the semiconductor laser through the use of a photodetector and comparing the monitoring result after sample hold and a laser power reference voltage.